GraphQL vs REST APIs: When & How to Choose

Choosing the right approach for data exchange can be an essential decision that can shape how efficient and successful your digital product becomes. Two of the top choices out there are GraphQL & REST APIs each with its pros and cons. For tech leaders, understanding the differences between these two isn’t just a technical detail - it’s a strategic decision that can impact your product’s performance and overall user experience.

Let us break down the key differences between GraphQL & REST APIs, focusing on where each approach shines. We’ll highlight the main factors to help you make an informed decision from data fetching techniques to their effects on app performance. Whether you are optimizing data interactions for a single-page app or scaling a complex platform, this guide will offer insights to help you choose the right API solution.

What is GraphQL?

GraphQL serves as a query language for APIs. It also functions as a runtime to execute those queries with your existing data. Developed by Facebook in 2012 and later released as an open-source project in 2015. GraphQL offers an adaptable option compared to REST APIs. It empowers clients to request the exact data they require, resulting in enhanced efficiency and minimized data transfer across the network.

Here are some key features and concepts of GraphQL:

• Client-specified queries: In GraphQL, clients can structure the format of the response where they can specify exactly which fields they need from an API that reduces over-fetching and under-fetching. This flexibility allows developers to customize their requests according to the requirements of their applications.
  
  
• Single endpoint: GraphQL APIs have a single endpoint where all data requests are made to this endpoint using a POST method with the query included in the request body which makes API structure simpler and management easier.
  
  
• Strongly typed schema: GraphQL APIs are structured by a schema that outlines the types of data that can be queried and the relationships between them. This acts as a contract between the client and server that provides clear documentation and enables tools for validation and introspection.
  
  
• Real-time capabilities: GraphQL supports real-time updates using subscriptions where clients can subscribe to specific events that allow them to receive updates automatically when data changes which is particularly useful for applications that require live data such as chat apps or collaborative tools.
  
  
• Efficient data loading: Using GraphQL, clients can collect data from multiple sources in a single request. This means that even if the data is stored across different services or databases, clients can retrieve it in one go which reduces the number of network requests and improves performance.

What is REST API?

A REST API (Representational State Transfer Application Programming Interface) is a specific implementation of the REST architectural style, which is designed to enable communication between a user and a server over the web. It allows developers to access and manipulate resources using standard HTTP methods, which helps to create a consistent and predictable interface for applications. 

Let’s explore the key features of REST API: 

• Resource-Based: Resources are the primary objects of interaction in a REST API. Each resource is associated with a unique URL (Uniform Resource Locator). 
  
  
• Statelessness: REST APIs operate in a stateless manner which means that every request from the client to the server must include all the necessary information for the server to understand and process it. The server doesn’t store any information about the client between requests which enhances scalability and simplifies management.
  
  
• Standard HTTP Methods: REST APIs employ standard HTTP methods to perform operations on resources:
• GET: Retrieve data from the server like getting a list of users.
• POST: Creating a new resource on the server like adding a new user.
• PUT: Updating an existing resource such as changing user details.
• DELETE: Remove a resource from the server like deleting a user.
• Format Independence: REST APIs can deliver data in various formats including JSON and XML. 
  
  
• Cachability: Responses from a REST API can be cached, improving performance by minimizing the number of requests sent to the server. This is especially beneficial for data that doesn’t change often.
  
  
• Layered Architecture: REST APIs can be organized into multiple layers allowing for the integration of load balancing, security features, and other services without the client being aware of the underlying complexities.

What are the Key Differences Between REST & GraphQL?

1) Data Fetching & Flexibility:

• REST: REST APIs have a fixed structure that requires multiple endpoints to represent various resources. Each resource is associated with a specific URL which leads to a requirement for separate requests for each piece of data. This rigid structure can cause inefficiencies as clients must navigate through multiple endpoints to collect related information.
  
  
• GraphQL: In contrast, GraphQL operates through a single endpoint that lets clients send a query that specifies exactly what data they need. This approach lets clients retrieve precisely the required data in a single request which results in a more efficient data-fetching process.

2) Efficiency & Performance:

• REST: REST APIs frequently encounter issues related to over-fetching and under-fetching. Over-fetching occurs when a client retrieves more data than required as the endpoint returns a predefined set of fields. On the other hand, under-fetching happens when a client has to make multiple requests to gather all the required information, resulting in heightened latency and performance obstacles.
  
  
• GraphQL: GraphQL addresses these issues by enabling clients to customize their queries to fetch only the specific data they require. This focused data retrieval boosts performance by reducing payload sizes and minimizing the number of requests which leads to a more efficient use of network resources.

3) Versioning

• REST: Versioning in REST APIs can be complex and challenging. As applications evolve, changes may require the introduction of new versions to maintain backward compatibility. This often results in separate endpoints for different versions, which can lead to resource fragmentation and increased maintenance overhead.
  
  
• GraphQL: GraphQL eliminates the need for versioning by allowing flexible schema evolution. Developers can add new fields or types to the existing schema without breaking existing queries. This approach enables incremental changes without disrupting the API's usability, leading to a more sustainable development process.

4) Error Handling:

• REST: In REST APIs, error handling typically relies on standard HTTP status codes to indicate the outcome of an operation. While this provides a basic understanding of errors, the information conveyed through status codes may not offer sufficient context for troubleshooting.
  
  
• GraphQL: GraphQL utilizes a more descriptive approach to error handling. When an error occurs, the response includes detailed information about the error which includes messages and relevant path information within the query. This rich error data aids developers in understanding and addressing issues effectively which results in a better user experience and smoother debugging processes.

ALSO READ: The Role of APIs in Bridging AI and Legacy Systems

When is GraphQL the Best Fit for Your API Needs?

GraphQL can be a great choice over traditional REST APIs in certain situations, especially where flexibility and efficiency are crucial. Here are some ideal scenarios to consider:

• Complex Data Structures: If your app needs to retrieve data that are linked across multiple sources, GraphQL lets you pull in just the data you need with one request to save resources and improve speed.
  
  
• Frequent Frontend Changes: When the frontend interface requires rapid updates, GraphQL makes it easy to adjust data requests without waiting for backend changes which allows developers to keep up with fast-paced updates.
  
  
• Mobile Applications: For mobile apps, where data usage needs to be optimized, GraphQL’s ability to customize queries helps limit the amount of data being transferred which leads to quicker load times and better user experience.
  
  
• Over-fetching or Under-fetching: If you're frequently encountering scenarios where you either get too much or too little data from your API, GraphQL helps mitigate this issue by allowing clients to specify their exact data needs.
  
  
• Multiple Data Sources: If your application aggregates data from various services or databases, GraphQL can serve as a unified interface to simplify data retrieval from disparate sources through a single endpoint.
  
  
• Real-Time Updates: Applications needing live data such as messaging platforms or collaborative tools - benefit from GraphQL’s subscription features which support real-time updates.
  
  
• Improving Developer Experience: With its strong typing and introspection features, GraphQL helps developers quickly understand available data and methods to ease onboarding and speed up the app development process.
  
  
• Simplifying API Versioning: If managing multiple API versions is becoming a challenge, GraphQL can simplify things by allowing clients to choose the data they need often making traditional versioning unnecessary.
  
  
• Microservices Architecture: In microservices-based architectures, GraphQL can serve as a bridge between different services, offering a cohesive way to retrieve data without needing to call each service separately.

ALSO READ: SOAP vs REST API: 10 Differences You Need To Know

When Should You Opt for REST API?

Choosing a REST API can be the right decision in many cases, particularly when simplicity and standardization are key. Here are some scenarios where REST is a good fit:

• Simple Data and Static Endpoints: If your application has straightforward data requirements without complex relationships, REST’s approach to defined endpoints works effectively which makes it easier to design & maintain.
  
  
• CRUD Operations: REST is well-suited to create, read, update, and delete (CRUD) functions, as its HTTP methods - like GET, POST, PUT, and DELETE - align perfectly with these operations.
  
  
• Caching Needs: REST’s reliance on HTTP allows for simple caching of responses which is useful in scenarios where caching can help reduce load times and server demands.
  
  
• Predictable Structure: REST APIs have a clear, predictable structure that makes them easier for developers to work with. This is ideal when you want a consistent and standard approach for your API.
  
  
• No Real-Time Data Needs: Since REST is stateless, it doesn’t natively support real-time updates. For applications where real-time data isn’t essential, REST can be simpler to manage.
  
  
• Broad Compatibility: REST is widely supported across languages and platforms which makes it a good option if your application needs to integrate with other systems or external services.
  
  
• Lower Complexity: When you don’t need to handle deeply nested data or call multiple data sources in one request, REST’s straightforward architecture can simplify development and reduce technical overhead.
  
  
• Microservices Communication: REST works well with microservices as each service can be set up with specific endpoints which makes it easier to organize & maintain the interactions between services.
  
  
• Lightweight Requirements: REST APIs are often simpler to implement and can be a perfect choice for projects with limited resources or relatively straightforward applications.
  
  
• Strong Security Practices: REST can be set up with common web security practices, like HTTPS and token-based authentication, securing the API in line with standard security measures easier.

ALSO READ: The Role of APIs in Streamlining HealthTech Data Integration

What to Consider When Choosing Between GraphQL and REST for Your App?

While Adopting GraphQL:

• Schema Design & Planning: GraphQL requires a well-designed schema that defines data types, fields, and relationships, which can be complex in large applications. A poorly crafted schema can lead to inefficient queries and performance issues. To avoid this, invest time in schema planning, considering future data needs and creating a flexible design to reduce constant changes and ensure optimal performance as your application scales.
  
  
• Query Complexity and Performance: GraphQL lets clients to make complex nested queries which can strain server resources if not optimized. It's important to implement query complexity analysis and set limits on query depth to mitigate this risk. 
  
  
• Caching & Optimization: Unlike REST, GraphQL does not have built-in support for HTTP caching which can affect performance for frequently requested data. Implementing caching with GraphQL often requires custom configurations or third-party tools. To address this, consider using server-level caching strategies or leveraging GraphQL client-side tools that offer caching capabilities. 
  
  
• Security Concerns: GraphQL's introspection feature can expose sensitive schema information and its single endpoint may be vulnerable to Denial of Service (DoS) attacks due to unrestricted query depths. To mitigate these risks, disable introspection in production, implement query complexity analysis, and use authentication and authorization middleware to control data access.

While Adopting REST API: 

• Endpoint Maintenance & Management: As applications expand, managing multiple endpoints can lead to endpoint sprawl with the need for new or versioned endpoints To mitigate this, use best practices for versioning such as including the version in the URL or header, and design APIs with the flexibility to support future modifications while minimizing the impact on existing endpoints.
  
  
• Overfetching & Underfetching Issues: REST's fixed endpoint structure can result in over-fetching or under-fetching data, especially in applications with diverse client needs, leading to wasted bandwidth. To address this, use query parameters to offer optional data fields as needed. If these issues persist, consider combining REST with GraphQL for parts of your application that require more precise data control.
  
  
• Versioning & Backward Compatibility: REST APIs often require versioning to manage changes, leading to the simultaneous support of multiple API versions and making backward compatibility cumbersome. To address this, establish a clear versioning policy from the outset and define the support duration for each version. Utilizing API gateways can simplify the transition between versions by efficiently routing versioned requests for clients.
  
  
• Caching: While REST APIs can utilize HTTP caching, maintaining cache consistency across multiple endpoints and clients can be challenging, especially with frequently changing data that may lead to stale information. To manage this effectively, use HTTP headers like Cache-Control and ETag to control caching behavior. For frequently updated, implement appropriate caching policies that balance freshness and performance, and consider server-side caching solutions to reduce database query load.

Wrapping Up

Choosing between GraphQL and REST APIs ultimately depends on your project’s needs, resources, and long-term vision. Each has strengths: GraphQL shines in flexibility, efficient data fetching, and real-time capabilities, making it ideal for complex data structures, mobile applications, and fast-evolving frontends. It empowers clients to fetch precisely the data they need while avoiding issues of over-fetching and under-fetching common in REST APIs. However, its added complexity, especially in schema design and caching, may require careful planning and specific expertise.

Conversely, REST APIs offer simplicity, predictability, and strong support for stateless interactions. They are well-suited to simpler data structures, CRUD operations, and applications that benefit from standardized HTTP-based caching. REST’s widely adopted structure and compatibility make it ideal for straightforward or resource-constrained applications.

By understanding the strengths and limitations of each approach, you can select the best-fit API for your development goals. Ultimately, successful implementation lies not just in choosing an API style, but in aligning it with your project’s scalability, performance, and maintenance requirements. A balanced approach may even offer the optimal solution for more versatile and future-proof applications.

Need help choosing the right API for your application? Our custom API development &  integration services can help you select and implement the perfect solution, whether it’s GraphQL or REST to ensure your app’s performance, scalability, and seamless user experience, schedule a no-obligation consultation with our experts now!